Extension-ladder lock.



O. R. CONABBE.

EXTENSION LADDER LOOK.

APPLIGATION FILED JAILB, 1914.

1,113,413.. Patented Oct. 13, 1914.

2 SHEETS-SHEET 1.

"lllllllllll THE NORRIS PETERS CO1. PHOTO-L!THO., WASHINGTON. D. C.

c. R. GONABEE.

EXTENSION LADDER LOCK.

APPLIOAUON FILED JAN. 6, 1914.

Patented Oct. 13, 1914.

Z SHEETS-SHEET 2 mwzam M THE NORRIS PETERS co, PHOTO-LITHO.. WASHINGTON, D, C.

human STATES rarnnrrornicn.

CHARLES R. CONABEE, OF BUTLER, PENNSYLVANIA.

EXTENSION-LADDEB LOCK.

Specification of Letters Patent. Application filed January 6, 1914. Serial No. 810,595

Patented Oct. .13, 19,14.

To all whom it may concern p I Be 'it known that I, CHARL S R. CoNAnEn a citizen of the United States of America,

and resident of Butler, Pennsylvania, have I invented a new and useful Improvement in Extension-Ladder, Locks, which lnventlon is fully set forth in the following specification.

The present invention relates to extension ladders, and particularly is an improvement in the devices employed to secure to gether the two sections of the ladder. These devices are usually attached to the upper ormovable section and are provided with pivoted hooks that engagev the rungs of the lower section.

The objects of the invention are to provide through the side guard and hook. This makes a deviceof great strength, simplicity and compactness. cover is associated with the parts, said'cover being mounted on the means. that pass through the side guard and hook. Further, positive action ofthe hook to move the same into position over theru ngs of the stationary section is effected by a trip which yields only upwardly, said trip being pivoted to saidhook above the pivotal point of the latter, and having a cam surface thatengages the lower face of the rungs of thestationary ladder to effect the movement of said hook.

By this means, when the trip engages the under face of a rung on the lower section, the hook isposltively moved to a positlon immediately over the neXt lower rung, and

when the hook engages the under face of a rung on the lower section, the trip is positively moved to a position immediately below the next higher rung. Further, when it is desired to lower the upper sec*, tion, said trip readily yields as it engages the upper face of each of the rungs of the lower section that it passes.

Preferably, a caslng' or- Theinvention' will be better understood by reference tothe accompanying drawing,

illustrating one expression ofthe inventive idea,"and wherein p y i i v F1gure 1 1s a perspective view. showing the lower ends of a stationary and movable section, the upper part of each of these sections being broken away; Fig. 2 is an enlarged vertical section on the, line 22 of Fig. 1, looking in the direction of the ar-,

rows; Fig. 3 is a transversesection on the line 3-3 of Fig. 2, looking'in the direction ofthe arrows; and Fig. 4: is a view showing the several parts of the improveddevice pulled out or'separated to better illustrate their construction and theway they are as-v sembled and disassembled. p j

' Referring to the drawings,' wherein like reference characters indicate like parts, A indicates generally the lower ladder or section, B the upper ladder or section, and C the combined side guard orguide and hook member for securing the sections'in extended position. It lsto be understood that more than two sections maybe employed and that, while a, single device C may be used to connect two sections, two such devices are preferably employed, one being secured to each'side rail oflthe section B. F Inasmuch,

however, as the construction andoperation 0f each areidentical, it will only be necessary to describe one. i

. Referring particularlyito Figs. 3 and 4, 55 indicates a side guard or guide that is suitably secured to the side rail 6 of the upper or movable ladder section. 'This guard or guide is preferably provided with substantially parallel members 7 and 8 that engage opposite faces of said side rail 6, said member being connected by an integral part 9 that'engage's the edge of saidside rail 6. The member 8 is provided with a perforated stud or projection 10, preferably formed integrally therewith, and in the preferred embodiment of the inventive idea said guard or guide is secured to the side rail 6eby a bolt 11 that passes through members 7 and 8,

siderail 6 and stud 10. Preferably, too,

additional securing means are provided in the form' of screws passing through holes 12 and 13 (Fig.4) in part 9. The guard or guide 5 is provided with a part that engages the outer face of one of the side rails 14: of the lower or stationaryladder section, and

being pivotally mounted on the side guard; 5, the stud 1O snugly engagingin an open-l ing 18 in said member. It has been experienced that, by mounting the hook member on the side guard, there is secured a device of great strength, simplicity, and'compactness, thus largely reducing the danger of' breakage and accident. Preferably, a cover or caslng is employed to protect the parts and, as here shown, said casing consists of a-face plate 19 (Fig. 4) and a part 20 which latter is provided With a. cut-out portion 21 in which the member 8 of the guard or guide fits. Said part 20 is also provided with projections 22 and 23 that engage one edge of the side rail 6, this construction insuring a close fit of the cover to the other parts. Fur ther, said cover is provided, preferably integrally, with a rib or ridge 24 against which bears a spring 25, one end of .which is secured to the part 20 at 26. The function o-f'this spring is to positively hold the hook member 17 in either of the two positions to which it may have been shifted. When the hook member has been shifted into position to engage a rung on the lower or stationary section (Fig. 2), the free end of said spring will engage a 'cam face 27 (Fig.4) provided near the pivot of said hook and will hold the hook positively in that position; whereas, when "the parts are shifted to thefull line position shown in Fig. 2, the spring will en gage a cam face 28 to hold the parts in said full line position. v H v As will be observed, the present device is so constructed and applied to the upper or movable section that it is unnecessary to remove a rung from said section to mount the device thereon, which removal would weaken the section; and, further, when the upper and lower sections are secured in extended position by the improved device, the.

rungs on the two sections are opposite one another. I I g The hook 17 is automaticallyshifted into positidn to engage the desired rung on the lower section by meansof a positivelyacting trip 29 that is pivoted at 30 to a bifurcated projection 31, preferably formed integrally with said hook 17. This trip is enlarged or .i'veighted' at 32,so that when the parts are, in the full line position shown in Fig. 2, sa'id trip will always 'b'eimmediately below the next higher rung on the lower or stationary section. Further, said trip is provided with an inclined or cam surface 33, and when the upper or movable section is being raised,,the engagement of this cam surface with the lower face of the next higher rung-34l (Fig. 2) for example,- effects the positive movement of the parts from the full to the dotted line position shown in Fig. 2. hen the trip is in the full line position indicated, a shoulder 35 engages a face 36 of the projection 31, so that said trip can only move upwardly when it engages the rungs of the lower or station- W i l V ary section and, when the movable section is being elevated, this engagement of shoul der 35 and face 36 causes the trip and hook to move positively as a unit when the former engages the under faces of the rungs of the lower section. I l

The operation of the device is as follows: l/Vhen the parts are assembled in position, the upper and lower sections will be held together during relative movement by the side guard or guide with the parts in the position shown in full'lines in Fig. 2. If it is desired to engage the projection 37 of the hook 17 with the rung 38 of the stationary section, the movable section of the ladder is elevated in any suitable manner, thus engaging the cam surface 33 with the lower face of the rung 34. which causes the hook to be swung around its pivot toward the right, (as shown in Fig. 2) against the tension of spring 25. The hook will thus assume a position immediately above that shown in dotted lines and, if the upper section is then lowered, the parts will be moved to the dotted line position, with the projection 37 in engagement with the rung 38. The parts are held positively in this position by the engagement of spring 25 with cam face 27. It will be observed that, in the dotted line position, the trip 29 is out of line fwith the rungs of the stationary section. To lower the movable section, it is first elevated until the surface 39 of the hook 17 engages rung 34, which causes said hook to swing aroundits pivot, thus moving prdjection 37 to the left out 'of line with the rungs on the stationary section, and at the same time moving trip 29 to the right in line with said rungs; with cam surface 28 holds the parts posi tively in this position. In view of the fact that the trip 29 is free to move upwardly around itsp'ivo't 30, as the upper section is lowered, said trip will yield as it engages each rung of the lower section and, in such lowering operation, said trip is the only part moving with the hook 17 that contacts with the rungs of the lower section. It will thus be understood that, in elevating the movable section, the engagement of the trip with ucceedin'g rungs of the stationary section forces the hook into position to engage said The engagement of spring 25 rungs, whereas the engagement of surface 39 forces the hook out of line with the rungs of the stationary section and the trip into line therewiththe cam surface 33 and surface 39 alternately engaging the under face of each succeeding rung of the lower section as the upper section is raised.

It is pointed out that the improved device is so constructed that it may be assembled either on the right or left-hand side of a ladder section, without change of any kind.

WVhile one expression of the inventive idea has been herein described in detail, it is to be understood that the inventive idea is not limited to the structure illustrated but may receive various mechanical expressions conforming to thedefinition of the invention contained in the following claims.

lVhat is claimed is 1. In an extension ladder comprising movable and stationary sections, the combination of a side guard or guide carried by the movable section, a hook member mounted on said side guard, means automatically moving said member into position to engage the rungs of the stationary section, and a bolt passing through said side guard and hook member.

2. In an extension ladder comprising upper and lower sections, the combination of a side guard mounted on and engaging the side of the upper section at diametrically opposite points, a hook member mounted on said guard and automatically engaging the rungs on the lower section, and a bolt passing through said side guard at two points and through said hook member.

3. In an extension ladder comprising 11 per and lower sections, the combination 0 a side guard mounted on and engaging opposite faces of the side. of the upper section, a hook member mounted on said guard and automatically engaging the rungs on the lower section, and a bolt passing through said sideguard at two points and through said hook member.

4. In an extension ladder comprising upper and lower sections, the combination of a side guard mounted on one side of the upper section and having a stud or projection thereon, a hook member mounted on said projection, and means securing said side guard and member in place.

5. In an extension ladder comprising upper and lower sections, the combination of a side guard mounted on one side of the upper section and having a stud or projection thereon, a hook .member mounted on said projection, and a bolt passing through the side of said ladderand said projection.

6. In an extension ladder comprising. upper and lower sections, the combination of a side guard mounted on one side of the upper section and having a stud or projection thereon, a hook member mounted on said projection, a bolt passing through the side of said ladder and said projection, and a cover mounted on-said bolt.

7..In an extension ladder comprising upper and lower sections, the combination of section, a hook member mounted on said side guard, a bolt passing through said parallel members, the side of the upper section and said hook member, and a cover mounted on,

said bolt.

9. In an extension ladder comprising up per and lowerv sections, the combinationof a s1de guard having parallel members engaging opposite faces of one side of the upper sectlon and an extenslon engagmg the lower section, a projection formed on one of said members, a hook member mounted on said pro ection, and a bolt passlng through said side of the upper sectionand said projection.

10. In an extension ladder comprising upper and lower sections, the combination of a side guard having parallel members engaging opposite faces of one side of the upper section and an extension engaging* the lower section, a projection formed on one of said members, a hook member mounted on said projection, a bolt passing through said side of the upper section and said projection, and a cover mounted on said bolt.

11. In an extension ladder comprising upper and lower sections, the combination of a pivoted hook member on the upper section, a trip pivotally mounted on said hook member above the pivot point of the latter,

said trip having an inclined, face that engages the lower face of the rungs on the lower section to positively move saidmember over a rung below that engaged by said trip.

per and lower sections, the combination of a pivoted hook member on the upper section, a trip pivotally mounted on said hook mem' ber above the pivot point of the latter and moving only upwardly, said-trip having an inclined face that engages the lower face of the rungs on the lower section to posi-.

tively move said member over a rung below that engaged by said trip.

13. Inan extension ladderv comprising upper and lower sections, the combination 12. In an extension ladder comprising up-' of a pivoted hook member on the upper sec- 7 In" "testimony whereof I have signed this tion, a weighted trip pivotally mounted on specification in the preseinceof two-subse'rib- 10 said hook member above the pivot point of mg Witnesses.

the latt'r, said trip havin an inclined face w" that engages the lower fa c e of'the rungs on CHARLES CONABEE the lower section to positively move said Titnessie's:

member over a rung below that engaged by J AMES E. MARSH-ALL,

said trip. THOMAS W. WATSON.

copies of this atent ma be obtained for eye cents each, py aaaressin'g the commissioner of Patents, Wa'hington, DIG. 

